The U.S. created 600,000 new millionaires last year—the fastest growth since at least the early 1990s. And increasingly, the big wealth drivers in America are oil and tech.

Dallas was home to the fastest-growing population of new millionaires in 2013, according to a new report from Capgemini and RBC Wealth Management. The number of millionaires in that city jumped 20 percent to 113,000.

Ranking second was Houston—another big energy town—with 18 percent growth in millionaires. Houston added 20,000 new millionaires, bringing the city's total to 131,000 millionaires with a total net worth of $496 billion.